I'm running my room on a raspberry pi and it has been doing great so far ;)

if you go with a cloudbox, go with the cheapest you can find imho.
Before I moved picoroom into my house it ran on a 5 dollar digital ocean ubuntu box (and I ran 2 or 3 nginx sites on that box too).

if you want to play on the save side (and you don't care too much that your cloudbox provider has to swap out hard drives from time to time) you could follow this guide i wrote long long ago to add some swap to your linux box for extra memory.

Swap isn't too healthy for SSDs (lotsa rewrites), and I would recommend you never do this on physical SSD drives you own :p.

ssb-room isn't too hard on your system, so you could try without first!